Answer: Nucleotide; Adenine
Explanation: RNA Nucleotide contains bases of Thymine, Cytosine, Guanine and Uracil. The Uracil base in RNA, substitute the base Thymine in the DNA base and bonds with Adenine like as seen in DNA base pairing.
Thus, during DNA duplication, the thymine at the top of the template strand of DNA is replaced with Uracil and binds with Adenine.